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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
commit4f5791ebd03eaec1c7da0865a383175b05102712 (patch)
tree8ce7b00f7a76baa386372422adebbe64510812d4 /source4/ntvfs/common/brlock_tdb.c
parentInitial commit. (diff)
downloadsamba-4f5791ebd03eaec1c7da0865a383175b05102712.tar.xz
samba-4f5791ebd03eaec1c7da0865a383175b05102712.zip
Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'source4/ntvfs/common/brlock_tdb.c')
-rw-r--r--source4/ntvfs/common/brlock_tdb.c775
1 files changed, 775 insertions, 0 deletions
diff --git a/source4/ntvfs/common/brlock_tdb.c b/source4/ntvfs/common/brlock_tdb.c
new file mode 100644
index 0000000..77a864a
--- /dev/null
+++ b/source4/ntvfs/common/brlock_tdb.c
@@ -0,0 +1,775 @@
+/*
+ Unix SMB/CIFS implementation.
+
+ generic byte range locking code - tdb backend
+
+ Copyright (C) Andrew Tridgell 1992-2006
+ Copyright (C) Jeremy Allison 1992-2000
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* This module implements a tdb based byte range locking service,
+ replacing the fcntl() based byte range locking previously
+ used. This allows us to provide the same semantics as NT */
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "messaging/messaging.h"
+#include "lib/messaging/irpc.h"
+#include "libcli/libcli.h"
+#include "cluster/cluster.h"
+#include "ntvfs/common/brlock.h"
+#include "ntvfs/ntvfs.h"
+#include "param/param.h"
+#include "dbwrap/dbwrap.h"
+
+/*
+ in this module a "DATA_BLOB *file_key" is a blob that uniquely identifies
+ a file. For a local posix filesystem this will usually be a combination
+ of the device and inode numbers of the file, but it can be anything
+ that uniquely idetifies a file for locking purposes, as long
+ as it is applied consistently.
+*/
+
+/* this struct is typicaly attached to tcon */
+struct brl_context {
+ struct db_context *db;
+ struct server_id server;
+ struct imessaging_context *imessaging_ctx;
+};
+
+/*
+ the lock context contains the elements that define whether one
+ lock is the same as another lock
+*/
+struct lock_context {
+ struct server_id server;
+ uint32_t smbpid;
+ struct brl_context *ctx;
+};
+
+/* The data in brlock records is an unsorted linear array of these
+ records. It is unnecessary to store the count as tdb provides the
+ size of the record */
+struct lock_struct {
+ struct lock_context context;
+ struct ntvfs_handle *ntvfs;
+ uint64_t start;
+ uint64_t size;
+ enum brl_type lock_type;
+ void *notify_ptr;
+};
+
+/* this struct is attached to on oprn file handle */
+struct brl_handle {
+ DATA_BLOB key;
+ struct ntvfs_handle *ntvfs;
+ struct lock_struct last_lock;
+};
+
+/* see if we have wrapped locks, which are no longer allowed (windows
+ * changed this in win7 */
+static bool brl_invalid_lock_range(uint64_t start, uint64_t size)
+{
+ return (size > 1 && (start + size < start));
+}
+
+/*
+ Open up the brlock.tdb database. Close it down using
+ talloc_free(). We need the imessaging_ctx to allow for
+ pending lock notifications.
+*/
+static struct brl_context *brl_tdb_init(TALLOC_CTX *mem_ctx, struct server_id server,
+ struct loadparm_context *lp_ctx,
+ struct imessaging_context *imessaging_ctx)
+{
+ struct brl_context *brl;
+
+ brl = talloc(mem_ctx, struct brl_context);
+ if (brl == NULL) {
+ return NULL;
+ }
+
+ brl->db = cluster_db_tmp_open(brl, lp_ctx, "brlock", TDB_DEFAULT);
+ if (brl->db == NULL) {
+ talloc_free(brl);
+ return NULL;
+ }
+
+ brl->server = server;
+ brl->imessaging_ctx = imessaging_ctx;
+
+ return brl;
+}
+
+static struct brl_handle *brl_tdb_create_handle(TALLOC_CTX *mem_ctx, struct ntvfs_handle *ntvfs,
+ DATA_BLOB *file_key)
+{
+ struct brl_handle *brlh;
+
+ brlh = talloc(mem_ctx, struct brl_handle);
+ if (brlh == NULL) {
+ return NULL;
+ }
+
+ brlh->key = *file_key;
+ brlh->ntvfs = ntvfs;
+ ZERO_STRUCT(brlh->last_lock);
+
+ return brlh;
+}
+
+/*
+ see if two locking contexts are equal
+*/
+static bool brl_tdb_same_context(struct lock_context *ctx1, struct lock_context *ctx2)
+{
+ return (cluster_id_equal(&ctx1->server, &ctx2->server) &&
+ ctx1->smbpid == ctx2->smbpid &&
+ ctx1->ctx == ctx2->ctx);
+}
+
+/*
+ see if lck1 and lck2 overlap
+
+ lck1 is the existing lock. lck2 is the new lock we are
+ looking at adding
+*/
+static bool brl_tdb_overlap(struct lock_struct *lck1,
+ struct lock_struct *lck2)
+{
+ /* this extra check is not redundant - it copes with locks
+ that go beyond the end of 64 bit file space */
+ if (lck1->size != 0 &&
+ lck1->start == lck2->start &&
+ lck1->size == lck2->size) {
+ return true;
+ }
+
+ if (lck1->start >= (lck2->start+lck2->size) ||
+ lck2->start >= (lck1->start+lck1->size)) {
+ return false;
+ }
+
+ /* we have a conflict. Now check to see if lck1 really still
+ * exists, which involves checking if the process still
+ * exists. We leave this test to last as its the most
+ * expensive test, especially when we are clustered */
+ /* TODO: need to do this via a server_id_exists() call, which
+ * hasn't been written yet. When clustered this will need to
+ * call into ctdb */
+
+ return true;
+}
+
+/*
+ See if lock2 can be added when lock1 is in place.
+*/
+static bool brl_tdb_conflict(struct lock_struct *lck1,
+ struct lock_struct *lck2)
+{
+ /* pending locks don't conflict with anything */
+ if (lck1->lock_type >= PENDING_READ_LOCK ||
+ lck2->lock_type >= PENDING_READ_LOCK) {
+ return false;
+ }
+
+ if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) {
+ return false;
+ }
+
+ if (brl_tdb_same_context(&lck1->context, &lck2->context) &&
+ lck2->lock_type == READ_LOCK && lck1->ntvfs == lck2->ntvfs) {
+ return false;
+ }
+
+ return brl_tdb_overlap(lck1, lck2);
+}
+
+
+/*
+ Check to see if this lock conflicts, but ignore our own locks on the
+ same fnum only.
+*/
+static bool brl_tdb_conflict_other(struct lock_struct *lck1, struct lock_struct *lck2)
+{
+ /* pending locks don't conflict with anything */
+ if (lck1->lock_type >= PENDING_READ_LOCK ||
+ lck2->lock_type >= PENDING_READ_LOCK) {
+ return false;
+ }
+
+ if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK)
+ return false;
+
+ /*
+ * note that incoming write calls conflict with existing READ
+ * locks even if the context is the same. JRA. See LOCKTEST7
+ * in smbtorture.
+ */
+ if (brl_tdb_same_context(&lck1->context, &lck2->context) &&
+ lck1->ntvfs == lck2->ntvfs &&
+ (lck2->lock_type == READ_LOCK || lck1->lock_type == WRITE_LOCK)) {
+ return false;
+ }
+
+ return brl_tdb_overlap(lck1, lck2);
+}
+
+
+/*
+ amazingly enough, w2k3 "remembers" whether the last lock failure
+ is the same as this one and changes its error code. I wonder if any
+ app depends on this?
+*/
+static NTSTATUS brl_tdb_lock_failed(struct brl_handle *brlh, struct lock_struct *lock)
+{
+ /*
+ * this function is only called for non pending lock!
+ */
+
+ /* in SMB2 mode always return NT_STATUS_LOCK_NOT_GRANTED! */
+ if (lock->ntvfs->ctx->protocol >= PROTOCOL_SMB2_02) {
+ return NT_STATUS_LOCK_NOT_GRANTED;
+ }
+
+ /*
+ * if the notify_ptr is non NULL,
+ * it means that we're at the end of a pending lock
+ * and the real lock is requested after the timout went by
+ * In this case we need to remember the last_lock and always
+ * give FILE_LOCK_CONFLICT
+ */
+ if (lock->notify_ptr) {
+ brlh->last_lock = *lock;
+ return NT_STATUS_FILE_LOCK_CONFLICT;
+ }
+
+ /*
+ * amazing the little things you learn with a test
+ * suite. Locks beyond this offset (as a 64 bit
+ * number!) always generate the conflict error code,
+ * unless the top bit is set
+ */
+ if (lock->start >= 0xEF000000 && (lock->start >> 63) == 0) {
+ brlh->last_lock = *lock;
+ return NT_STATUS_FILE_LOCK_CONFLICT;
+ }
+
+ /*
+ * if the current lock matches the last failed lock on the file handle
+ * and starts at the same offset, then FILE_LOCK_CONFLICT should be returned
+ */
+ if (cluster_id_equal(&lock->context.server, &brlh->last_lock.context.server) &&
+ lock->context.ctx == brlh->last_lock.context.ctx &&
+ lock->ntvfs == brlh->last_lock.ntvfs &&
+ lock->start == brlh->last_lock.start) {
+ return NT_STATUS_FILE_LOCK_CONFLICT;
+ }
+
+ brlh->last_lock = *lock;
+ return NT_STATUS_LOCK_NOT_GRANTED;
+}
+
+/*
+ Lock a range of bytes. The lock_type can be a PENDING_*_LOCK, in
+ which case a real lock is first tried, and if that fails then a
+ pending lock is created. When the pending lock is triggered (by
+ someone else closing an overlapping lock range) a messaging
+ notification is sent, identified by the notify_ptr
+*/
+static NTSTATUS brl_tdb_lock(struct brl_context *brl,
+ struct brl_handle *brlh,
+ uint32_t smbpid,
+ uint64_t start, uint64_t size,
+ enum brl_type lock_type,
+ void *notify_ptr)
+{
+ TDB_DATA kbuf, dbuf;
+ int count=0, i;
+ struct lock_struct lock, *locks=NULL;
+ NTSTATUS status;
+ struct db_record *locked;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+
+ if (brl_invalid_lock_range(start, size)) {
+ return NT_STATUS_INVALID_LOCK_RANGE;
+ }
+
+ locked = dbwrap_fetch_locked(brl->db, brl, kbuf);
+ if (!locked) {
+ return NT_STATUS_INTERNAL_DB_CORRUPTION;
+ }
+
+ /* if this is a pending lock, then with the chainlock held we
+ try to get the real lock. If we succeed then we don't need
+ to make it pending. This prevents a possible race condition
+ where the pending lock gets created after the lock that is
+ preventing the real lock gets removed */
+ if (lock_type >= PENDING_READ_LOCK) {
+ enum brl_type rw = (lock_type==PENDING_READ_LOCK? READ_LOCK : WRITE_LOCK);
+
+ /* here we need to force that the last_lock isn't overwritten */
+ lock = brlh->last_lock;
+ status = brl_tdb_lock(brl, brlh, smbpid, start, size, rw, NULL);
+ brlh->last_lock = lock;
+
+ if (NT_STATUS_IS_OK(status)) {
+ talloc_free(locked);
+ return NT_STATUS_OK;
+ }
+ }
+
+ dbuf = dbwrap_record_get_value(locked);
+
+ lock.context.smbpid = smbpid;
+ lock.context.server = brl->server;
+ lock.context.ctx = brl;
+ lock.ntvfs = brlh->ntvfs;
+ lock.context.ctx = brl;
+ lock.start = start;
+ lock.size = size;
+ lock.lock_type = lock_type;
+ lock.notify_ptr = notify_ptr;
+
+ if (dbuf.dptr) {
+ /* there are existing locks - make sure they don't conflict */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ if (brl_tdb_conflict(&locks[i], &lock)) {
+ status = brl_tdb_lock_failed(brlh, &lock);
+ goto fail;
+ }
+ }
+ }
+
+ /* no conflicts - add it to the list of locks */
+ /* FIXME: a dbwrap_record_append() would help here! */
+ locks = talloc_array(locked, struct lock_struct, count+1);
+ if (!locks) {
+ status = NT_STATUS_NO_MEMORY;
+ goto fail;
+ }
+ if (dbuf.dsize > 0) {
+ memcpy(locks, dbuf.dptr, dbuf.dsize);
+ }
+ locks[count] = lock;
+
+ dbuf.dptr = (unsigned char *)locks;
+ dbuf.dsize += sizeof(lock);
+
+ status = dbwrap_record_store(locked, dbuf, TDB_REPLACE);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto fail;
+ }
+
+ talloc_free(locked);
+
+ /* the caller needs to know if the real lock was granted. If
+ we have reached here then it must be a pending lock that
+ was granted, so tell them the lock failed */
+ if (lock_type >= PENDING_READ_LOCK) {
+ return NT_STATUS_LOCK_NOT_GRANTED;
+ }
+
+ return NT_STATUS_OK;
+
+ fail:
+ talloc_free(locked);
+ return status;
+}
+
+
+/*
+ we are removing a lock that might be holding up a pending lock. Scan for pending
+ locks that cover this range and if we find any then notify the server that it should
+ retry the lock
+*/
+static void brl_tdb_notify_unlock(struct brl_context *brl,
+ struct lock_struct *locks, int count,
+ struct lock_struct *removed_lock)
+{
+ int i, last_notice;
+
+ /* the last_notice logic is to prevent stampeding on a lock
+ range. It prevents us sending hundreds of notifies on the
+ same range of bytes. It doesn't prevent all possible
+ stampedes, but it does prevent the most common problem */
+ last_notice = -1;
+
+ for (i=0;i<count;i++) {
+ if (locks[i].lock_type >= PENDING_READ_LOCK &&
+ brl_tdb_overlap(&locks[i], removed_lock)) {
+ if (last_notice != -1 && brl_tdb_overlap(&locks[i], &locks[last_notice])) {
+ continue;
+ }
+ if (locks[i].lock_type == PENDING_WRITE_LOCK) {
+ last_notice = i;
+ }
+ imessaging_send_ptr(brl->imessaging_ctx, locks[i].context.server,
+ MSG_BRL_RETRY, locks[i].notify_ptr);
+ }
+ }
+}
+
+
+/*
+ send notifications for all pending locks - the file is being closed by this
+ user
+*/
+static void brl_tdb_notify_all(struct brl_context *brl,
+ struct lock_struct *locks, int count)
+{
+ int i;
+ for (i=0;i<count;i++) {
+ if (locks->lock_type >= PENDING_READ_LOCK) {
+ brl_tdb_notify_unlock(brl, locks, count, &locks[i]);
+ }
+ }
+}
+
+
+
+/*
+ Unlock a range of bytes.
+*/
+static NTSTATUS brl_tdb_unlock(struct brl_context *brl,
+ struct brl_handle *brlh,
+ uint32_t smbpid,
+ uint64_t start, uint64_t size)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct *locks, *lock;
+ struct lock_context context;
+ struct db_record *locked;
+ NTSTATUS status;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+
+ if (brl_invalid_lock_range(start, size)) {
+ return NT_STATUS_INVALID_LOCK_RANGE;
+ }
+
+ locked = dbwrap_fetch_locked(brl->db, brl, kbuf);
+ if (!locked) {
+ return NT_STATUS_INTERNAL_DB_CORRUPTION;
+ }
+ dbuf = dbwrap_record_get_value(locked);
+
+ context.smbpid = smbpid;
+ context.server = brl->server;
+ context.ctx = brl;
+
+ /* there are existing locks - find a match */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+
+ for (i=0; i<count; i++) {
+ lock = &locks[i];
+ if (brl_tdb_same_context(&lock->context, &context) &&
+ lock->ntvfs == brlh->ntvfs &&
+ lock->start == start &&
+ lock->size == size &&
+ lock->lock_type == WRITE_LOCK) {
+ break;
+ }
+ }
+ if (i < count) goto found;
+
+ for (i=0; i<count; i++) {
+ lock = &locks[i];
+ if (brl_tdb_same_context(&lock->context, &context) &&
+ lock->ntvfs == brlh->ntvfs &&
+ lock->start == start &&
+ lock->size == size &&
+ lock->lock_type < PENDING_READ_LOCK) {
+ break;
+ }
+ }
+
+found:
+ if (i < count) {
+ /* found it - delete it */
+ if (count == 1) {
+ status = dbwrap_record_delete(locked);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto fail;
+ }
+ } else {
+ struct lock_struct removed_lock = *lock;
+ if (i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ count--;
+
+ /* send notifications for any relevant pending locks */
+ brl_tdb_notify_unlock(brl, locks, count, &removed_lock);
+
+ dbuf.dsize = count * sizeof(*locks);
+
+ status = dbwrap_record_store(locked, dbuf, TDB_REPLACE);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto fail;
+ }
+ }
+
+ talloc_free(locked);
+ return NT_STATUS_OK;
+ }
+
+ /* we didn't find it */
+ status = NT_STATUS_RANGE_NOT_LOCKED;
+
+ fail:
+ talloc_free(locked);
+ return status;
+}
+
+
+/*
+ remove a pending lock. This is called when the caller has either
+ given up trying to establish a lock or when they have succeeded in
+ getting it. In either case they no longer need to be notified.
+*/
+static NTSTATUS brl_tdb_remove_pending(struct brl_context *brl,
+ struct brl_handle *brlh,
+ void *notify_ptr)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct *locks;
+ NTSTATUS status;
+ struct db_record *locked;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+
+ locked = dbwrap_fetch_locked(brl->db, brl, kbuf);
+ if (!locked) {
+ return NT_STATUS_INTERNAL_DB_CORRUPTION;
+ }
+
+ dbuf = dbwrap_record_get_value(locked);
+ if (!dbuf.dptr) {
+ talloc_free(locked);
+ return NT_STATUS_RANGE_NOT_LOCKED;
+ }
+
+ /* there are existing locks - find a match */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ if (lock->lock_type >= PENDING_READ_LOCK &&
+ lock->notify_ptr == notify_ptr &&
+ cluster_id_equal(&lock->context.server, &brl->server)) {
+ /* found it - delete it */
+ if (count == 1) {
+ status = dbwrap_record_delete(locked);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto fail;
+ }
+ } else {
+ if (i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ count--;
+ dbuf.dsize = count * sizeof(*locks);
+ status = dbwrap_record_store(locked, dbuf,
+ TDB_REPLACE);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto fail;
+ }
+ }
+
+ talloc_free(locked);
+ return NT_STATUS_OK;
+ }
+ }
+
+ /* we didn't find it */
+ status = NT_STATUS_RANGE_NOT_LOCKED;
+
+ fail:
+ talloc_free(locked);
+ return status;
+}
+
+
+/*
+ Test if we are allowed to perform IO on a region of an open file
+*/
+static NTSTATUS brl_tdb_locktest(struct brl_context *brl,
+ struct brl_handle *brlh,
+ uint32_t smbpid,
+ uint64_t start, uint64_t size,
+ enum brl_type lock_type)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct lock, *locks;
+ NTSTATUS status;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+
+ if (brl_invalid_lock_range(start, size)) {
+ return NT_STATUS_INVALID_LOCK_RANGE;
+ }
+
+ status = dbwrap_fetch(brl->db, brl, kbuf, &dbuf);
+ if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+ return NT_STATUS_OK;
+ } else if (!NT_STATUS_IS_OK(status)) {
+ return status;
+ }
+
+ lock.context.smbpid = smbpid;
+ lock.context.server = brl->server;
+ lock.context.ctx = brl;
+ lock.ntvfs = brlh->ntvfs;
+ lock.start = start;
+ lock.size = size;
+ lock.lock_type = lock_type;
+
+ /* there are existing locks - make sure they don't conflict */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+
+ for (i=0; i<count; i++) {
+ if (brl_tdb_conflict_other(&locks[i], &lock)) {
+ talloc_free(dbuf.dptr);
+ return NT_STATUS_FILE_LOCK_CONFLICT;
+ }
+ }
+
+ talloc_free(dbuf.dptr);
+ return NT_STATUS_OK;
+}
+
+
+/*
+ Remove any locks associated with a open file.
+*/
+static NTSTATUS brl_tdb_close(struct brl_context *brl,
+ struct brl_handle *brlh)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i, dcount=0;
+ struct lock_struct *locks;
+ struct db_record *locked;
+ NTSTATUS status;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+
+ locked = dbwrap_fetch_locked(brl->db, brl, kbuf);
+ if (!locked) {
+ return NT_STATUS_INTERNAL_DB_CORRUPTION;
+ }
+ dbuf = dbwrap_record_get_value(locked);
+ if (!dbuf.dptr) {
+ talloc_free(locked);
+ return NT_STATUS_OK;
+ }
+
+ /* there are existing locks - remove any for this fnum */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ if (lock->context.ctx == brl &&
+ cluster_id_equal(&lock->context.server, &brl->server) &&
+ lock->ntvfs == brlh->ntvfs) {
+ /* found it - delete it */
+ if (count > 1 && i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ count--;
+ i--;
+ dcount++;
+ }
+ }
+
+ status = NT_STATUS_OK;
+
+ if (count == 0) {
+ status = dbwrap_record_delete(locked);
+ } else if (dcount != 0) {
+ /* tell all pending lock holders for this file that
+ they have a chance now. This is a bit indiscriminant,
+ but works OK */
+ brl_tdb_notify_all(brl, locks, count);
+
+ dbuf.dsize = count * sizeof(*locks);
+
+ status = dbwrap_record_store(locked, dbuf, TDB_REPLACE);
+ }
+ talloc_free(locked);
+
+ return status;
+}
+
+static NTSTATUS brl_tdb_count(struct brl_context *brl, struct brl_handle *brlh,
+ int *count)
+{
+ TDB_DATA kbuf, dbuf;
+ NTSTATUS status;
+
+ kbuf.dptr = brlh->key.data;
+ kbuf.dsize = brlh->key.length;
+ *count = 0;
+
+ status = dbwrap_fetch(brl->db, brl, kbuf, &dbuf);
+ if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+ return NT_STATUS_OK;
+ } else if (!NT_STATUS_IS_OK(status)) {
+ return status;
+ }
+ *count = dbuf.dsize / sizeof(struct lock_struct);
+
+ talloc_free(dbuf.dptr);
+
+ return NT_STATUS_OK;
+}
+
+static const struct brlock_ops brlock_tdb_ops = {
+ .brl_init = brl_tdb_init,
+ .brl_create_handle = brl_tdb_create_handle,
+ .brl_lock = brl_tdb_lock,
+ .brl_unlock = brl_tdb_unlock,
+ .brl_remove_pending = brl_tdb_remove_pending,
+ .brl_locktest = brl_tdb_locktest,
+ .brl_close = brl_tdb_close,
+ .brl_count = brl_tdb_count
+};
+
+
+void brl_tdb_init_ops(void)
+{
+ brlock_set_ops(&brlock_tdb_ops);
+}